Shape fills such as solid colors, gradients, pictures, and textures can have a Transparency attribute that lets you reduce the opacity of a fill so that the slide object or background behind shows through. Transparency is calculated in percentages and you can change its value all the way from 0 to 100%. Some fill options, such as pattern and slide background have no Transparency options.

To learn more, choose your version of PowerPoint. If we do not have a tutorial for your version of PowerPoint, explore the version closest to the one you use.